I was perusing website a few days ago and ran across the routing/bussing schematics for a "feedback compressor." Now I can't find the page and I'm wondering what exactly a "feedback compressor" is? What are the merits of a feedback compressor? How do you route it? I remember vaguely that there was a sidechain, a delay and duplicated bussing. Can anyone explain?

If it's routing schematics then I'm thinking it was most likely describing how to set up controllable feedback loops on an analog mixer. Essentially it's a routing setup where it creates a feedback loop and then buss' it out to another fader acting as it's master. It could have potentially had a compressor or gate on it's master and when side-chained you could have rhythmically triggered feedback with it's own adjustable adsr due to the compressor or gate's variable parameters.

An extreme version of this would be called a "No-Input Mixer" as employed by the likes of Japanese extreme noise artist Masami Akita (Merzbow) and now a whole slew of other noise artists. The general technique is that an analog mixer output is connected to it's inputs to create a feedback loop. The sound is then shaped by eq's and insert fx. When it's been shaped as much as desired the sound is then sent out an aux to an external source for additional mixing and monitoring. And like I said before, if you set up side-chain fed gate's and compressors you can achieve rhythmic results that you can shape depending on how flexible your dynamics processors are.

Here's a few examples of these more extreme variations of what I seem to think you're talking about: